1. Field of the Invention
The present invention relates to a carrier supporting apparatus for supporting a carrier containing, therein, a plurality of substantially plate-like objects to be processed, for example, semiconductor wafers, such that each wafer is arranged vertically at an interval in a horizontal attitude.
2. Background Art
For example, in the case of carrying out a test for a semiconductor wafer by using a testing device, such as a probe, the wafer is carried out from a carrier and then carried into the testing device, by using a carrying arm, so as to perform the test without providing any adjustment to the wafer. In this case, the wafer itself is not cut into individually separated chips, but all chips to be subjected to a cutting process will remain integrally to collectively constitute the wafer.
In some cases, the semiconductor wafer is attached to a film and a test is carried out for the wafer while the film is supported by a dicing frame around the wafer. (Hereinafter, the wafer, film and dicing frame in such a state as describe above will be collectively referred to as “an object to be processed”, and, for convenience, such an object to be processed will also be simply referred to as “a dicing frame”). In this case, the wafer associated with the dicing frame is typically fixed onto the film while cut (or diced) into individual chips. Upon testing, for example, 25 sheets, of dicing frames are placed, in advance, in an exclusive carrier while they are each arranged vertically in the carrier at an interval, taking a horizontal attitude. Thereafter, the carrier is placed on a carrier supporting apparatus located adjacent a testing device. In this way, each dicing frame is carried between the carrier and the testing device by using a carrying arm.
For example, as shown in FIG. 3, a carrier C used exclusively for the dicing frames has a pair of left and right side plates 1, 1, and a plurality of connecting rods 2 for connecting top ends of the side plates 1, 1 together. The carrier C also includes at least one guide rod 3 for connecting bottom ends of the side plates 1, 1 together. The guide rod 3 is composed of a flat bar 3A and a piece of projection 3B formed along a bottom face of the flat bar 3A. The carrier C is positioned and placed at a predetermined location on a carrier supporting apparatus via the projection 3B of the guide rod 3.
A typical example of the carrier C has 25 sets of supporting stages 1A, 1A provided vertically at an interval. Each set of the supporting stages 1A, 1A are configured to support left and right edges at a bottom face of each one dicing frame D. Specifically, in an inner face of each side plate 1, 25 grooves 1A are provided vertically at an interval. The bottom face of each groove 1A constitutes each supporting stage.
Upon placing the dicing frames D in the carrier C, each dicing frame D supported by the carrying arm 20 is inserted horizontally between one set of grooves 1A, 1A, and thereafter the carrying arm is lowered. In this manner, the dicing frame D is supported on each supporting stage which is a bottom face of the one set of grooves 1A, 1A, in which the dicing frame D is inserted. Upon taking out each dicing frame D from the carrier C, the carrying arm 20 is inserted below a targeted dicing frame D, and is then lifted upward, thereby to raise the dicing frame D from the supporting stages 1A, 1A. Thereafter, the dicing frame D is pulled out from the carrier C while being supported by the carrying arm 20.
In the carrier C described above, as shown in FIG. 3(b), a gap δ1 (e.g., 3.49 mm) between the lowermost stages (i.e., bottom faces of the lowermost grooves 1A) and a top face of the flat bar 3A of the guide rod 3 is narrower than a gap δ2 (e.g., 4.85 mm) between each adjacent pair of the supporting stages. In addition, the former gap δ1 is slightly larger than a thickness T (e.g., 2.50 mm) of the carrying arm. Therefore, upon taking out the lowermost dicing frame D, the final gap (δ1−T) to be defined between the dicing frame D and guide rod 3 and the carrying arm 20 is significantly small (which is, for example, 3.49−2.50=0.99 mm). Therefore, the control of the carrying arm 20 is very difficult, and there is a risk of damaging the carrying arm 20 and/or dicing frame D. Accordingly, it is virtually impossible to support and carry out the lowermost dicing frame D by using the carrying arm 20.
As such, although the carrier C, apparently, has a capacity for containing 25 sheets of dicing frames D therein, the lowermost supporting stages 1A, 1A have not been used in the past, and only 24 sheets of dicing frames D were contained in the carrier C. Thus, the storage efficiency of the carrier C for the dicing frames D has been insufficient.